METHOD AND DEVICE FOR LOADING AN INSTALLATION WITH FIBRES

Abstract

The invention relates to a method and an apparatus for feeding an installation with fibres, which installation is fed with fibre tufts, the fibre tufts are opened at least partially and fed by means of a feed apparatus to a pneumatic feeding installation, which guides the fibres into the reservoir of at least one fibre-processing machine, especially a flat card, roller card, opener or cleaner.

The invention is characterised in that, by means of a regulating circuit into which the actual pressure values measured and further processed in the pneumatic feeding installation are introduced, and into which the mass flow of the further processed fibres measured and further processed at at least one fibre-processing machine is introduced, the optimal operating point of the installation is determined by means of a regulating algorithm, and a signal is passed to an actuator of the feed apparatus for regulating the amount of fibre tufts.

Claims

1. Method for feeding an installation with fibres, which installation is fed with fibre tufts, the fibre tufts are opened at least partially and fed by means of a feed apparatus to a pneumatic feeding installation, which guides the fibres into the reservoir of at least one fibre-processing machine, especially a flat card, roller card, opener or cleaner, characterised in that, by means of a regulating circuit into which the actual pressure values measured and further processed in the pneumatic feeding installation are introduced, and into which the mass flow of the further processed fibres measured and further processed at at least one fibre-processing machine is introduced, the optimal operating point of the installation is determined by means of a regulating algorithm, and a signal is passed to an actuator of the feed apparatus for regulating the amount of fibre tufts.

2. Method according to claim 1, characterised in that the mass flow of the further processed fibres, the pressure difference between a reference variable and a regulating variable, and the difference between the desired production rate and the actual production rate of the mass flow of the further processed fibres are introduced into the regulating circuit.

3. Method according to claim 1 or 2, characterised in that the signal for regulating the feed apparatus is fed back into the regulating circuit, where it again passes through the regulating algorithm.

4. Method according to any one of the preceding claims, characterised in that the actual pressure values which are measured in the pneumatic feeding installation are converted by a differentiation over time into a corrected actual pressure value, and the resulting difference, with a desired pressure value, is introduced into the regulating circuit.

5. Method according to any one of the preceding claims, characterised in that, for starting up the spinning room preparation installation, the regulating algorithm starts from a constant mass flow of fed fibre tufts.

6. Method according to any one of the preceding claims, characterised in that planned or unplanned fluctuating production amounts of at least one fibre-processing machine are processed in the regulating circuit.

7. Method according to any one of the preceding claims, characterised in that fluctuations in the pneumatic feeding installation through the determined fibre running time are introduced into the regulating circuit.

8. Method according to any one of the preceding claims, characterised in that the maximum amount of fed fibre tufts can be set manually.

9. Method according to any one of the preceding claims, characterised in that the desired pressure in the pneumatic feeding installation can be set manually.

10. Apparatus for feeding an installation with fibres, which installation is fed with fibre tufts, the fibre tufts are opened at least partially and fed by means of a feed apparatus to a pneumatic feeding installation, which guides the fibres into the reservoir of at least one fibre-processing machine, especially a flat card, roller card, opener or cleaner, characterised in that, by means of a regulator (X2) which is part of a regulating circuit into which the actual pressure values (p1) measured and further processed in the pneumatic feeding installation are introduced, and into which the mass flow ({dot over (m)}1) of the further processed fibres measured and further processed at at least one fibre-processing machine is introduced, the optimal operating point of the installation is determined by means of a regulating algorithm, and a signal (z) is passed to an actuator of the feed apparatus for regulating the amount of fibre tufts ({dot over (m)}2).

11. Apparatus according to claim 10, characterised in that a signal relating to the mass flow ({dot over (m)}1) of the further processed fibres, a signal (v) relating to the pressure difference between the reference variable and the regulating variable, and a signal (u) relating to the difference between the desired production rate and the actual production rate of the mass flow ({dot over (m)}1) of the further processed fibres are introduced into the regulator (M2).

12. Apparatus according to claim 10 or 11, characterised in that the signal (z) for regulating the control variable at the feed apparatus is fed back into the regulator (X2), where it passes through the regulating algorithm again.

13. Apparatus according to any one of the preceding claims 10 to 12, characterised in that the actual pressure values (p1) measured in the pneumatic feeding installation are converted by a differentiation over time into a corrected actual pressure value (y) and compared in a regulator (X3) with a desired pressure value, and the resulting difference is introduced as a signal (v) into the regulating circuit.

14. Apparatus according to any one of the preceding claims 10 to 13, characterised in that planned or unplanned fluctuating production amounts of at least one fibre-processing machine are introduced as a signal (w) into the regulator (X2).

15. Apparatus according to any one of the preceding claims 10 to 14, characterised in that the fibre running time in the pneumatic feeding installation is measured and is introduced as a signal (t) into the regulator (X2).

16. Apparatus according to any one of the preceding claims 10 to 15, characterised in that the feed apparatus is in the form of a conveyor belt and/or feed roller (1a, 1b) which are driven via a regulatable drive, wherein the maximum speed of the drive (20) can be set manually.

17. Apparatus according to any one of the preceding claims 10 to 16, characterised in that the pneumatic feeding installation is in the form at least of a feed and distributor line (5), the desired pressure of which can be set manually.

Description

[0017] The invention will be described in greater detail by way of example with reference to the accompanying drawings, in which

[0018] FIG. 1 is a diagrammatic view of a spinning room preparation installation with a block diagram of the apparatus according to the invention;

[0019] FIG. 2 is a functional diagram of a spinning room preparation installation according to the prior art;

[0020] FIG. 3 is a functional diagram of an installation according to the invention during start up of the installation;

[0021] FIG. 4 is a functional diagram of the installation according to the invention in operation.

[0022] In the spinning room preparation installation according to FIG. 1, the fibre material F is fed from a bale opener (not shown) via a mixer (not shown) to a cleaner 1. From the last roller of the cleaner 1, the opened and cleaned fibres, or fibre tufts, are conveyed pneumatically via a pipeline 2, a dust-extraction machine 3 and a fan 4 into a pneumatic feed and distributor line 5, to which a tuft feeder 6 with at least one flat card 7 are connected.

[0023] The tuft feeder 6 has an upper reserve shaft 6a and a lower feed shaft 6b, between which a tuft-conveying device in the form of a slow-speed feed roller 6c and a high-speed opening roller 6d may be arranged. The feed roller 6c can cooperate, for example, with a feed tray (not shown) across the width of the tuft feeder 6. An inductive displacement sensor, which is connected by way of a computer to a regulator, can be associated with the feed tray. Changes in the mass of the fibre material being conveyed are thereby detected and converted into electrical signals.

[0024] In order to be able to determine the amount of fibre produced, there can be arranged at the outlet of each flat card 7 a sliver funnel (not shown) or an alternative apparatus, downstream of which are two delivery rollers, for example. The sliver funnel or the alternative apparatus has a sensor 14 with which the amount of fibre produced can be determined and which transmits corresponding signals for the mass flow {dot over (m)}1 to the regulators X1 and X2.

[0025] This can take place, for example, by a spring-loaded feeler tongue which is rotatable about a hinge. The feeler tongue cooperates with an inductive displacement sensor, which is connected to a regulator X1 and X2. In this manner, the amount of fibre produced, that is to say the mass flow {dot over (m)}1, can be determined by the sliver thickness in dependence on the sliver speed.

[0026] In practice, the signal for the mass flow {dot over (m)}1 enters the flat card controller, which transmits this value, or an associated signal, to the regulators X1 and X2.

[0027] Mounted in a wall of the feed and distributor line 5 is a pressure sensor 8 which is connected to a measured value transducer 9. The measured actual pressure values p1 are thereby converted into electrical signals x and input into a controller 10, for example a computer. In the controller 10, an electrical signal y for a corrected actual pressure value is generated by differentiation of the pressure difference over time. The signal y with the corrected actual pressure value is again fed to an electronic regulator X3. By way of an input device 12, a desired pressure value can be input as a reference variable into the controller 10 and into the regulator X3. The difference between the reference variable and the regulating variable is input into the regulator X2 as signal v.

[0028] By measuring the actual pressure values p1 in the feed and distributor line 5 and the mass flow {dot over (m)}1 of the discharged fibre sliver at the flat card 7 and by comparing them with the reference variables, the regulating circuit determines the feed speed and thus the mass flow {dot over (m)}2 of fibres fed into the cleaner.

[0029] In order that the regulating circuit always finds the optimal operating point for the spinning room preparation installation during removal of material from the fibre bales without manual re-adjustment of fibre qualities or material fluctuations, the invention provides at least two regulators X1 and X2, regulator X1 being functionally separate from regulator X2 since there is no feedback from regulator X2 to X1. Regulator X1 requests the target desired production rate via the flat card controller and compares it with the current actual production rate. The difference between the desired production rate and the actual production rate enters the regulator X2 as signal u.

[0030] The regulator X2 can be in the form of a PI regulator which, on the assumption of slight fluctuations, starts from a known mass flow {dot over (m)}2 of fibres F and determines the optimal value for the flat card production rate by way of a computer on the basis of the current flat card production rate {dot over (m)}1. The regulator X2 thus starts from a constant fibre feed {dot over (m)}2 (estimated starting value), which can actually be subject to wide fluctuations, in order to determine the optimal operating point for the current flat card production rate with a mass flow {dot over (m)}1. This estimation of the starting value by the regulator X2 allows the start up of the installation at the actual optimal operating point to be accelerated. The optimal (stored) operating point from the last operation of the installation is used as the starting value for the constant fibre feed. By assuming a constant fibre feed {dot over (m)}2 of the regulator X2, the regulating circuit achieves an approximation to the optimal operating point of the flat cards 7 in a very short time.

[0031] In addition to the value from the signal u, the regulator X2 further processes the signal v for the difference of the reference variable and the regulating variable from the regulator X3. As a further value, the current flat card production rate {dot over (m)}1 minus the interference variable S1 for the variable degree of cleaning is processed in the regulator X2.

[0032] From these three signals u, v and {dot over (m)}1, the regulator X2 continuously determines the delivery amount of the tuft-feeding machine with the mass flow {dot over (m)}2. The associated signal z regulates the actuator drive 20 for the conveyor belt and the feed rollers 1a, 1b, whereby the amount of fibres F can increase or decrease. By way of the input device 13, the speed for the actuator drive 20 can be limited, in order to limit the maximum batch production rate for technological reasons. At the same time, the signal z for regulating the actuator drive 20 is fed back into the regulator X2, where it is indirectly compared with the signal u and optimised, taking account of the further signals v and {dot over (m)}1. Inside the regulator X2, the signal z is processed with the signal from the current fibre flow or mass flow {dot over (m)}1 and the result is processed with the result from the signals {dot over (m)}1, u and v, which were processed together, to give a new value or signal z. The sequence of the signals processed together in the regulator X2 is a fundamental basis for the regulating algorithm. Feedback of the signal z which has already been evaluated ensures a further passage through the regulating algorithm with a new value for the signal z, resulting in a differentiating behaviour.

[0033] By feeding back the signal z and comparing it indirectly with the signal u, the spinning room preparation installation is able to operate very continuously without fluctuations. The feedback of signal z provides a rapid adaptation to the current optimal operating point, whereby the regulating circuit optimises itself and can therefore be described as “self-learning”.

[0034] A further improvement can be achieved in that, from the controller or controllers of the flat cards, an impending can change or flat card stop, or renewed starting up of the flat card, is fed into the regulator X2 as a signal w in order to take account of an impending fluctuation in the production rate, which manifests itself by more or fewer fibres, optionally with a pressure change in the feed and distributor line 5.

[0035] The feed and distributor line 5 becomes longer with the number of flat cards 7, so that the material running times become longer and the pressure in the feed and distributor line 5 is thus subject to greater fluctuations. In order to take account of this, the material running time can be determined in the controller 10 as signal t and input into the regulator X2. It is thus possible to anticipate pressure fluctuations on the basis of the gradient of the pressure curve over the material running time and to compensate for them by the fan or fans 4 and/or the actuator drive 20.

[0036] For reasons of clarity, only one flat card 7 has been shown in FIG. 1. Usually, a plurality of flat cards is connected to the distributor line 5, all of which are fed by the fibre preparation installation (mixer, cleaner 1, dust-extraction machine 3), each flat card 7 having its own tuft feeder 6. Instead of being used for flat cards, the regulating circuit can also be used for any other fibre-processing machine or installation, such as web-forming machines or for spinning room preparation installations for filling fibre reservoirs.

[0037] The algorithm for the regulating circuit is such that variations in the material or the material properties, as well as fluctuations in the production rate and further interference factors such as, for example, the switching off of individual machines, are compensated for automatically by the regulating circuit by the feeding back of at least one signal (regulator X2). The regulating circuit continuously adapts to the optimal operating point and “learns” the production rate as well as the effects of changes on the basis of variations in the material properties. In addition, the non-deterministic linearity variations of the material-conveying machine are learned and compensated for. The “learning process” of the regulating circuit always takes place without manual action and automatically leads to an observance of the optimal operating point for the flat cards and constant filling of the feed shafts. By means of a suitable, automated estimated starting value (regulator X2), the start-up phase is reduced to a minimum. It is no longer necessary to program the regulating circuit with fibre data. Only the damping of the regulating circuit on the basis of the dead time in the case of a greater pipe length, for example when the feed and distributor line 5 is lengthened due to further flat cards, must be adjusted. The only input values required are the desired pressure value in the input device 12 and the maximum speed in the input device 13. Material-specific data are no longer required because the regulating circuit automatically seeks and adapts to the optimal operating point.

[0038] Although not explicitly disclosed in the exemplary embodiment, the regulating circuit can also process further interference variables such as, for example, the degree of contamination of the fibre tufts, sliver breakage at the flat cards or fluctuating moisture in the fibre tufts.

[0039] The regulators X1, X2 and X3 are preferably accommodated in a common assembly group and do not need to be in the form of separate components.

[0040] The graphs in FIGS. 2 to 4 show on the abscissa the time in seconds. The left ordinate shows the pressure in pascals in the feed and distributor line 5, as well as the speed in % and the production rate in kg/h. The right ordinate shows an abstract dimensionless regulating value.

[0041] FIG. 2 shows a conventional solution according to the prior art, in which a regulator with manual operating point and fixed regulating calculation is used. The desired speed of the conveyor belt and of the feed rollers 1a, 1b, the desired production rate and the regulating value calculation are specified manually. Fluctuations in the material properties at a constant production rate can be compensated for only by manually adjusting the operating point.

[0042] Short-time fluctuations in the current production rate (x-axis: at 50-79 seconds and at 90-115 seconds) likewise cannot reliably be compensated for. This leads to considerable fluctuations in the pressure curve (1100 Pa to 1450 Pa), which differs considerably from the desired pressure of 1250 Pa. This in turn leads to complete stoppages in the supply (regulating value 0) of the feeding machine (the drives for the feed belt and the feed rollers 1a, 1b stop) and thus to defects in the density of the filling of the following machines, for example the flat cards.

[0043] The first-time learning phase is shown in FIG. 3, in which the desired production rate is optimised automatically and start up is in stages because the flat cards are gradually connected. At the same time, the actual pressure in the feed and distributor line 5 falls and approaches the desired pressure after about 220 seconds. The actual production rate coincides with the desired production rate after about 300 seconds. As the carding machines are started up or switched on, the actual speed of the drive for the conveyor belt or for the feed rollers 1a, 1b also increases gradually. A subsequent starting up of the installation takes place in a shorter time, because the last optimal operating point is stored in the regulator X2 and serves as the starting level for start-up.

[0044] FIG. 4 shows the continuous adaptation of the optimal operating point. Fluctuations in the material properties at a constant production rate (see left-hand part of the diagram) are compensated for by means of the “learning function” (feedback of at least one signal). In the middle and in the right-hand part of the diagram, there are fluctuations in the production rate which are compensated for in the same manner, the actual production rate being below the desired production rate for a short time. Owing to the feedback of at least one signal into the regulating circuit, all adjustments can be compensated for automatically, without manual action and without fluctuations in the filling or losses of production. The optimal operating point falls back slightly and finds its optimum when, after short-time fluctuations, the actual pressure has approached the desired pressure. A stop in the delivery to the feeding machine and thus a considerable fluctuation in the filling of the following machine can be completely prevented, and a uniform density and height in the filling, for example of the flat card shafts, can thus be achieved.

REFERENCE SIGNS

[0045] 1 Cleaner

[0046] 1a, 1b Feed rollers

[0047] 2 Pipeline

[0048] 3 Dust-extraction machine

[0049] 4 Fan

[0050] 5 Feed and distributor line

[0051] 6 Tuft feeder

[0052] 6a Reserve shaft

[0053] 6b Feed shaft

[0054] 6c Feed roller

[0055] 6d Opening roller

[0056] 7 Flat card

[0057] 8 Pressure sensor

[0058] 9 Measured value transducer

[0059] 10 Controller

[0060] 12 Input device

[0061] 13 Input device

[0062] 14 Sensor

[0063] 20 Actuator drive

[0064] F Fibre material

[0065] p1 Actual pressure value

[0066] t Signal

[0067] u Signal

[0068] v Signal

[0069] w Signal

[0070] x Signal

[0071] y Signal

[0072] z Signal

[0073] {dot over (m)}1 Mass flow of flat card

[0074] {dot over (m)}2 Mass flow of fibre tufts

[0075] S1 Interference variable

[0076] X1 Regulator

[0077] X2 Regulator

[0078] X3 Regulator